Dangerous issue. Leaf shifts into neutral and locks there while driving.

Wondering if this has happened to anyone else?

About 6 months ago my 2012 Nissan suddenly went into neutral while I was driving. It gave no audible alerts of any kind and would not shift back into drive. I could still steer and brake but it took several seconds to identify the message on the dash as i was doing about 60mph at the time and needed to pay attention to traffic. The error was ‘Ikey error - apply parking brake’. At 60mph in the middle of the highway applying the parking brake seemed a terrible idea so while rapidly slowing I maneuvered to the shoulder, thankfully I didn't get into an accident. After a few minutes of trying, I was finally able to figure a way to clear the error by disconnecting/reconnecting the 12v battery. Later I checked both the cars 12V battery and the transmitters 3v battery and both tested good. I tightened up the connections on the cars 12v battery and replaced the 3v just to be safe. I hoped it was just a one time glitch.

On Sunday 17th Dec 2022 I was driving when the car suddenly shifted into neutral and would not return to drive once again. Again this happen while I was driving the car and the car was in motion. Once again It had an Ikey error message. Key reconnect by holding key to power on button and turning car on failed. I was forced to unhook 12v battery to reset car. It happened a total of 4 more times before I was able to get the car home. The final time it happened in the middle of the highway at night. I had no way to get over and ended up stuck in the middle of a 4 lane highway. I was able to get the car going again by disconnecting the 12v battery but it took 4 tries with about 5-10 seconds each time with the battery disconnected (note disconnecting the battery turns off the cars flashers). Count myself lucky I didn’t get killed. I got the car home but this was very dangerous (BTW shifting a vehicle into neutral while driving is illegal in my state, wonder if I can file a charge against the design engineer?).

I the ‘ikey’ error was dealer diagnosed as an issue with the shift control. The drive system is not damaged, the vehicle was fully functional. Had the computer just given a warning and not taken control and shifted the car into neutral there would not have been an issue. Why have it shift into neutral and lock there? Don't know, it seems quite a dangerous thing to do while a vehicle is moving. The dealer wanted about $1,800 to replace the shift control. I found a used one on ebay for $80 and it took about 30min to replace. The car is back on the road and working again. Dealer also found one of the two pumps on my leafs coolant system was bad and wanted $2,000 to replace that, bought an aftermarket for about $50. There is no way I can feel safe driving unless someone can guarantee this won’t happen again. Given that the computer software used here is probably present in multiple vehicle models/years I think it's likely this is and issue with more than just this year and model car. That said I still do drive it, but with worries if this, or some other part failure, could cause a re-occurrence.

I've tired a couple of ways to contact Nissan with mild success. The latest response I received from them asked me to take the car back to the dealership, pay to have a diagnostic run, and send them the ticket number so they can investigate. Since the problem is already fixed I don't know what this is supposed to do. Honestly, why can't they just look up the previous diagnostic done back when the problem was actually present instead of costing me a day and $300? I have the old shifter, I can send it to them so they can reproduce the issue, wouldn't that be more effective? I guess when I get around to it ill do a tear down and testing on the old shifter to see what actually failed.

Thanks for the read
Eric

Nice work on the diagnosis and repair.

Without knowing more about the internal design of the system it's impossible to say if the part you replaced will fix the problem completely but it does seem reasonable that some sort of malfunction in the shifter would cause the car to shift to neutral. While that may not be the safest approach while on the freeway, it might be the safest all-around option. Eg, what would happen if the shifter malfunctioned while you were parking in the garage or backing up in a parking lot? One has to assume that there is a driver present at the time so putting the car in neutral so it doesn't move by itself is probably the least-worst option available.

My day job is programming computers to control mechanical things and in my experience, about 95% of the code and development time goes towards handling conditions like this where the sensors or feedback mechanisms fail. When everything is working, the control can be trivial or at least very straight forward. Trying to predict every possible failure point and how to handle them is the opposite of trivial. In this case I think that putting the car into neutral is the best option.

I'd suggest being a little extra careful while driving until you're sure the problem is fixed. Intermittent problems are always hard to track down but if you exceed 10x the previous failure interval without incident it is probably fixed.

Replacing the shifter did in deed fix the issue. I've been driving for a month or two with no re-occurrences. The main danger as I see it with the car dropping into neutral is that it does so while the car is on and while the car is in motion. If the kinetic energy of the car is not enough to get you to the shoulder you can end up stuck in the middle of traffic. Also shifting into neutral while the car is stopped is a serious problem as this is what left me stranded in the middle of the highway. Traffic had stopped and when I went to get moving again I found the car had shifted itself into neutral and would not go back into drive. There I am stuck in the middle lane at night with cars racing around me at 60MPH, somewhat unnerving, especially when I had to disconnect the battery (flashers) to try and reset the system. All vehicle systems should be designed to fail safe. And safe generally means giving the driver as much control as possible and clearly alerting the driver to the danger. I don't think shifting the car into neutral because of a communication loss with the shift control as safe in any way. I can think of no reason why the cars voice infotainment system could not have been setup to verbally inform me of the issue instead of making me try and diagnose the issue at 60MPH while trying to dodge traffic and get to the shoulder. I just wish Nissan would be more responsive when informed of a safety issue that could likely be fixed with a simple software change.